Carburizing box with inner surface resistant to carbon penetration



3, 1937. H. H. HARRIS 88,593

CARBURIZING BOX WITH INNER SURFACE RESISTANT TO CARBON PENETRATION Filed May 1, 1955 INVENTOR //E/VY b. HARP/6.

ATTORNEY5 Patented Aug. 3, 1937 UNITED STATES CARBURTZING BOX WITH INNER SURFACE RESISTANT T CARBON PENETRATION Henry H. Harris, Boston, Mass. Application May 1 1935, Serial No. 19,196

2 Claims.

My invention relates to carburizing boxes and has for its object to provide a carburizing box which is made of reduced porosity and increased my invention, the details being exaggerated for illustrative purposes; and

Fig. 2 is an enlarged similarly exaggerated sectional view through one wall thereof on the line 2-2.

The carburizing box I0 is made of suitable material, such as nickel-chromium-iron alloy, and by my invention same can be of relatively lower alloying constituents, such as lower nickel 20 and chromium by reason of the provision of the interior coating of nickel, etc., as stated, thereby obtaining equal life with lower expense for alloying constituents, or increased life for the same expense put into alloying constituents.

. The interior coating i2 may be applied in various ways but it is preferably applied by spraying with the well known Shoup gun it whereby the coating material is sprayed as it is melted.

While not always essential, the deposited metal 30 is preferably swedged to close up its surface grain and give it a smoother and better surface and to force the coating into any small depressions or irregularities in the original interior surface of the box.

carburizing box undergoing the treatment of A single coating is ordinarily suflicient, but plural applications may be made if desired, preferably with swedging after each application.

Nickel gives the best results when applied with the Shoup gun to the interior carburizing boxes of nickel and chromium alloy constituents, serving efiectually to close the pores and to give added resistance to carbon penetration, but materials such as copper and the like may be used to substantial advantage.

The materials used are preferably those having considerable pliability, ductility and toughness, and which are not greatly different in coefflcient of expansion from the alloy material to which the coating is applied so that parting and spalling are avoided in use under the high temperatures and severe conditions to which exposed, nickel and copper being well adapted in those respects. When the box alloy material comprises nickel,

a metallic coating also comprising nickel is well adapted for the purposes of my invention.

I claim:

1. Aparburizing box of alloy material comprising nickel, chromium, iron, etc., having a spray deposited interior surface layer of nickel.

2. The process of imparting enhanced chemical and physical resistance to carbon penetration to a carburizing box of an alloy material comprising nickel, chromium; iron, etc., which consists of spraying the interior surface of the box with nickel in molten, finely-divided state, thereby depositing a layer of nickel thereon.

HENRY H. BIS; 

